when block is placed on bottom-half of tall grass, a peony flower appears for a short moment

What I expected to happen was...:
The grass would disappear and the block I placed would still be there.

What actually happened was...:
The grass disappeared, but a very short moment later, a peony flower popped up where the grass was and then it disappeared again.

Steps to Reproduce:
1. place tall grass block
2. place a block on the bottom half of the tall grass